Call centre agents can expect to field between 50 and 200 calls a day, many of them in the evening. Many people complain of health problems. On top of that comes time pressure, bad work environments and low salaries.
"But it's a field that's exploding," says Erich Welthe, head of the ver.di Service Workers Union in Neubrandenburg-Greifswald. In the German state of Mecklenburg-Western Pomerania alone, around 13,000 people are employed in call centres, selling products, taking complaints or conducting surveys.
"The working conditions are difficult," says Welthe. Gross pay is between 5-6.5 euros ($7-9) an hour. But with only 30 hours a week, most employees rarely manage to scrape 800 euros together a month.
"Most call centre agents have to round off their income with state support."
But its not just the low pay that annoys Welthe. The hours of work are unacceptable, he bemoans.
Working conditions in call centres leave a lot to be desired, says labour economist Bernd Bienzeisler of the Fraunhofer Institute for Industrial Engineering in Stuttgart. Large rooms with 150 workers are standard.
"It's very stressful work. People can't be expected to be on the telephone for more than four hours consecutively."
Mental stress also runs high. "Call centres stipulate how long it should take to solve a customer's problem," explains Bienzeisler. Agents are often expected to solve a problem within 90 seconds. But customers can be frustrated and vent their anger on the agents.
Around 30,000 workers are employed in call centres across Germany, and the numbers are growing. Bienzeisler says no training is required to become an agent. Many of those employed in call centres are housewives or students trying to earn a little on the side.
"But now there's a trend towards qualified personnel, who have experience in the field," he says.
The high number of sick days call centre employees clock up indicates the enormous pressure exerted on them.
Last year, around 5.75 percent of workers with AOK, Germany's biggest health insurance company, called in sick, says Klaus Pelster, deputy director at the Institute for Advancement of Workplace Health in Cologne.
"That's a full percentage point higher than the average for the entire Rheinland region in Germany."
On an average, every call centre employee is officially registered as sick twice a year - which Pelster attributes mostly to stress and time pressure.
Of those workers who called in sick - around 25 percent suffered from respiratory problems. "They included cold symptoms, but also lung infections," said Pelster, who suspects people are straining their voices.
"The second biggest problem was muscular pain. Two thirds of all diagnoses point to back problems."
Beate Beermann, scientific director at the Federal Institute for Occupational Safety and Health in Dortmund, advises not to sit at a computer and telephoning continuously.
"There should be a 5-10 minute break every hour." Companies should allow employees access to rooms for relaxation.
"After all, customers notice when the agents are stressed." Regular education and diction training also encourages workplace motivation.